Mike00FRC

iTrader: (1)

Anyone know approximately how much AFR may be off on the dyno(dynojet) vs AFR for the same tune on the street(NA). I've heard that the AFR on a dyno is approx .5 lower than on the street as the load is not as great on the motor.

If this is true, if I want 12.9 or 13.0 AFR for the street/track, I should tune it for 12.4-5 on the dyno.

So, is there any truth to this?

Thanks,

Mike

SlickVert

iTrader: (5)

I have a wide band o2, on the dyno I am at 13.0 to 13.1. When on the street it goes to 12.5 to 12.6. As the speed increased it gets richer. I have a WS6 with the BGR ramair mod. I believe as the cars speed increases there is more pressurize air coming in and the MAF is reads more air an adding extra fuel.
To get the most out of your car you will need to tweak your tune at the track or street. Each car is different, so I would check it with a wide band 02 at the track or street.

1fastWS6

iTrader: (3)

Yeah, I just logged mine with a WB at the track last weekend. I was hovering around 12.8-13.0 on the dyno, and on the track it's around 12.9-13.0 in 1st and 2nd gears then gets richer 12.7-12.8 in 3rd and 4th.

Sunset01

I also found the seemingly ironclad 'you'll run at least 0.5 point leaner on the street' wrong too. I run almost identical AF dyno/street... and found optimal power at the same tune as well-meaning the car made the most power and ran the fastest set up exactly the same.

Mike K.

Same here I go from really lean on a dynojet to normal on a Mustang dyno with a load.

NicD

iTrader: (7)

I see about a tenth or two of a point difference in A/F on the dynojet vs the street.